Propeller



Patented July 11, 1933 UNITED vSTATES A THEODORE L. SMITH, OF DETROIT, MICHIGAN, ASSIGNR TO CAILIJE MOTOR COIVIPANY,al

PATENT OFFICE OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN rRorELLnR 'Application filed April 20,

This invent-ion relates to propellers and control means therefor.

r copending application, Serial No. 428,261,

filed February 14, 1930, I disclose an improved motor and propeller unit of this kind, the improvement including improved control arrangements for adjusting the pitch of the propeller` blades. 1

My present invention, which broadly is an improvement over the above mentioned patent and copending application, has for one of its objects the provision of an improved r arrangement for locking the propeller blades in position independently of the shitting col: lar and fork, an arrangement which eliminates the stress and wear on this collar and fork occasioned by the thrust placed on it by the blades. Vith the present invention the blades are locked in position and at the same time the shifting collar and fork are permitted to float freely.

Another object is the provision of a new and improved control arrangement for adjusting the pitch of the propeller blades and A particularly a new and 4improved control arrangement in which the control parts adjacent the propeller housing are encased in that housing and run in oil.

In the preferred embodiment of my inveni tion, the propeller consists of a hollow hub having blade members pivoted on its opposite sides, tlie pivot member of each of these '50 and is shiftable longitudinally of the-shaft by clamp .4. Asshown the motor cylinder 10 blades extending into the hollow interiori'y i of the hub and being provided with a pinion.

gear rigidly attached thereto. i 'Fitted within.the hub and around theshaft of the propeller is a rack which engages these gears.

1931. Serial-No. 531,405.

to adjust the pitch of thepropeller blades. The rack is moved longitudinally of the propeller shaft by a fork located within the propeller housing and controlled by a lever and link arrangement conneotedto thetiller bar of the motor. i y In the preferred embodiment of my invention, the blades are arranged so that when they are moved to one of their extreme positions the water pressure developed on their working surfaces as the propeller is rotated tends to rotate the blades about` tle pivots about which their Apitch is adjusted in the direction in which they Were'last moved, thereby locking them in their extreme positions. 'lhe thrust developed in the blades is resisted by the rack which engages stop members in the propeller hub when the blade is inv position yto drive the boat forward, and which are resisted by a thrust bearing when the blades are in position to drive the boat backward. In either case the rack resists hi: thrust independently of the shifting OI' I.

l/Vhen the blades .of the propeller are set in neutral or are set in positions intermediate of their extreme position, they are held by the rack and tiller bar as before.

My invention will thus be understood by reference to the accompanying drawings in which a preferred embodiment of it is shown by way of example and in which:

Figure 1 is a fragmentary elevational view, partly in section, showing an outboard motor equipped with my improved propeller;

' Figure 2 is a cross-sectional View taken along the line 2-2 of Figure l showing the propeller detail;

@Figure 3 1s an elevational view of the propeller;

peller showing the blades in position to drive the boat in a reverse direction.

Referring now to the drawings in more detail, themotor indicated generally at 1 is hung upon the stern board 2 of the boat by means of a bracket 3 and is'lattached thereto is disposed horizontally and connected to a vertical drive shaft 5 located in the tubular easing 6. The details yof the motor per se and its mounting upon the boat are not of 5 the essence of the present invention and are more fully explained in my above mentioned patent, to which reference is here made for the details of this construction.

Located at the bottom of the tubular casing 6' is a propeller casing 7 in which thepropeller shaft 8 is located, that propeller shaft being connected to the motor shaft 5 in any preferred manner suchas by the bevel gears9.

The propeller shaft 8 is supported in the propeller housing 7 by anti-friction bearings 10 and 11 which are arranged to rotatably support it and to resist the end thrust placed upon it by the propeller during its operation.

The shaft 8 extends through the rear wall member 12 of the propeller housing 7 and projects therebe ond, the hub 13 of the vpropeller being eyed to the projecting end ofthe shaft 8 by a key 19 and being formed 25 to tightly fit into the opening 14 in the wall 12, as shown in Figure 2.

The pro eller hub is hollow, and located "in it is a s ifting rack 15 which consists of a bifurcated cylinder having two arms lo- 30 cated `parallel to the shaft but spaced some distance away from it. These arms are provided with teeth 16 and 17 which engage pinions 18 and 19 respectively. The pinions are rigldl attached to the pivot shafts 20 35 and 21 o the propeller blades 22 and 23, 4 which blades are thereby pivotally mounted upon the hub 13. Nuts 24 threaded onto the ends of the ivots 20 and 21 lock the pinions on'the'bla es and the blades on the hub,

o these nuts being held against rotation on their threads by cotter pins 25.

The shifting rack 15 is threaded onto a sleeve 26 which surrounds the shaft 8 and is rotatable with respect thereto and also 45 slidable thereon. The attachment of the rack 15 to the sleeve may be made in any preferred manner such as by the screw thread as shown at 27. A A shifting collar 28 engages the sleeve 26 through a thrust bear- 0 ing 29, so that a movement of the collar 28 to the right in Figure 2 will move the sleeve longitudinally of the shaft 8. A second thrust bearing 30 bearing against the collar 28 and connected to the sleeve through a 55 washer 31 and a collar` 32 provides for moving the sleeve to the left in Figure 2 when the shifting collar is moved in that direction.

As will be seen in Figure 1, the pintles 33 of the collar 28 are engaged by the forked 5 lower end of a pivoted lever 3,4 located within the propeller housing 7 and pivoted within that housing at 35. The free end of the lever 34 is connected'by a link 36 to the control rod 37 which in turn is connected to the 35 tiller bar 38 which is pivoted at 39 to the motor frame. A movement of the tiller bar in a vertical plane about its pivot 39 will move the control rod 37 and cause it to rock the lever 34 about its pivot 35 and thereby move the fork to shift the sleeve 26 and rack 15 longitudinally of the propeller shaft 8. The tiller bar is provided with a detent engaging a rack 4l on the motor frame to lock it against movement in a vertical plane as will presently appeal'. The. latch 40 is controlled in any preferred n'ianner such as by a push button 42 located in the end of the tiller bar handle 43. lt will be, noted that the rack, sleeve, fork. lever and control rod arrangement herein described is the same as shown and fully described in my above mentioned copending application Serial No. 428,261, filed February 14, 1930.

Each propeller blade 22 and23 consists of a disk portion registering with and seated in' a counterbore 51 in the hub, and the blade, proper projects outwardly from the periphery of this disk member. As is clearly shown in Figure 3, the working face 52 of the propeller blade is offset with respect to the'pivotal axis about which the blade is rotated by the rack 15. As a result of this arrangement, when the propeller shaft 8 and hub 13 are rotated in the direction indicated by the arrow (Figure3), and the blade 23 has been rotated 1n a clockwise direction about its pivot to osition it to drive the boat for'- Wardly, t e edge 53 of the propeller blade becomes the leading edge.` As this leading edge 53 bites into the water in which the propeller is immersed, that water sets up a pressure against it and on the working face 52 of the propeller blade. Since this workin g face is out of the plane of the pivotal axis of the blade, this waterA ressure acts over a greater area of the wor ing -face 52 to the right of the axis of the pivot shaft on stud `20 than to the left of the axis of theshaft 20 which tends to rotate the blade in a clockwise direction about vits pivot. The greater area of the blade acted upon by the water pressure to the right of the dot and dash line a-a Figure) than to the'left of that line prouces a turning tendency in the blade which turning tendency holds the blade in open or set position without locking the blade in such position through the shifting collar` and without the stress upon the shiftin collar and other parts where such locking 1s necessary. The opposite blade -22 will of course be similarly positioneg and the water pressure on its leading edge 4 will develop a pressure which because the blade is offset with respect to its pivotal connection will develop a torque tending to rotate the blade in a counterclockwise direction, Figure 2. The turning tendency in this blade tends to hold it in open or set position as described in connection with the other blade. The torque of the blade lso 22 about the pitch adjusting pivot tends to move the rack to the left as viewed in Figure 2 to hold the stop pins 55 against the end its pinion the rack 15 is transmittedthrough the pins 55 to the propeller hub 13. This pressure is exerted in a direction longitudinally of the propeller shaft 8 and toward the rear end of thel boat, that is, it is in direct opposition to the main propeller thrust placed upon the shaft 8 by the propeller blades themselves. However, since the thrust developed by the tendency of the blades to rotate about their pivots is small as compared with the driving thrust of the blades, the boat is moved forwardly. This arrangement of transmitting the thrust developed'by-the tendency of the blades to rotate about'their pivotsv to the hub of the propeller in a direction opposite to that', placed upon the hub by the main propeller thrust, permits locking the blades in their forward position without increasing the frictional losses occasioned by this added end thrust.

The working faces 52 of the propeller blades are slightly concave and the trailing faces 57 are convex, these blades being shaped so that the concave face 52 is the main working face when the propeller is positioned to ldrive the boat forward.

' When the propeller blades are rotated about their pivots to drive the boat in a back- Ward direction, the blade 23 will be positioned as shown in Figure 5, and the sleeve 26 will be moved forwardly of the shaft 8 land made to bear against the thrust bearing 58 which surrounds that shaft. The leading edge 53 bites into the water as the propeller is rotated in the direction indicated by the arrow and the force set up in the propeller blade falls along a line located to the left of the pivotal axis of the blade, Figure 5, and consequently the blade is under tension which tends to rotate it in a counter-clockwise direction. This tension transferred into torque by the offset relation of the blade to its pivotal axis is communicated through the pinion 19 and teeth 17 to the rack 15 and thence to the sleeve 26, tending to urge that sleeve to the rightagainst the bearing 58. The stationary race -59 of this bearing is abutted aga-insta wall member 60 of the lpropeller housing 7, so that the end thrust of the sleevel 26 is taken up by the bearing 58 independently of the shaft bearings.

j Preferablythe blades are designed so that they operate most efficiently when adjusted to drive the boat forward since it is in that position that they will be most often used.

rEhe thrust placed on the rack under these circumstances is acting toward the back of the boat, and there need be no bearing through which this thrust is transmitted to the shaft without introducing frictional losses. When the blades are set to drive the boat in a reverse direction the thrust is absorbed by a bearing, but because of the shape of the blades this thrust is small and no great losses are incurred.

1f it is desired to operate the propeller in a position intermediate ofits extreme position it must be locked and the pawl.40 is used for this purpose. lVhen the blades are in neutral there is no thrust upon them in 'either direction and the fork is not under thrust and may therefore hold the blades in place without loss.

The propeller casing 7 is divided into compartments by integrally formed interior walls, and the entire casing is made oil-tight so that the motor shaft 5 and the bearing 5', the bevel gears 9, the propeller' shaft bearings 1U and 1l, the fork bearing and the rack within the propeller hub may all be immersed in oil or other suitable lubricant. rlhe fork shifting lever is likewise encased in this casing and immersed in oil so that 'frictional losses in the propeller head are maintained.

From the foregoing will be apparent that I have devised a new and improved reversible propeller which is capable of locking itself in its extreme positions independently of this shifting fork, and that the arrangement thus disclosed accomplishes this purpose by simple and inexpensive parts which While once properly adjusted may be operated over a long period of time without further attention. As shown the invention is applied to an outboard motor, this disclosure being made by way of example only as the improved propeller assembly may be 4used in connection with any type of small marine motor.

Having. thus complied with the statutes and shown and described a preferred embodiment of my invention what I consider new and desire to have protected by Letters Pat ent is pointed out in the appended claims.

1. An adjustable propeller ofthe class described comprising a blade, and a pivot for said blade, sa'id pivot beingy spaced laterally from one side of said blade in a plane generally normal to the side of he blade and intersecting the blade substantially centrally between the leading and trailing edges of said blade whereby the pressure upon the blade in operation acts upon a greater area of the blade in a direction tending to open the blade than in a direction tending to close the blade and at the same time the leverage in the blade against adjustment is substantially one-half the width of the blade.

2. An adjustable propeller of the class deilo scribed comprising a pair of diametrically opposite blades, coaxial pivots for said blade, said pivots being oifset laterally from the sides of the blades in planes generally normal to the sides of the blades and intersecting the blades substantially centrally between the leading and trailing edges of the blades whereby the pressure upon the blades in operation acts upon a greater area of the blades in directions tending to open the blades than in directions tending to close the blades and at the same timethc leverage in the blades against adjustment is substantially one-half the width of the blades.

3. An outboard motor comprising a generally vertical tubular post, an under-water unit disposed at the lower end of said post and including a housing part, a partition dividing the interior of said housing part.

into a pair of chambers, a drive shaft extending down through said post and into one of said chambers, a propeller shaft disposed generally normal the lower end of said drive shaft and geared to said drive shaft in onel of said chambers, said propeller shaft eX- tcnding through the partition and out externally of the housing through the other chamber, a bearing disposed in said partition for journaling said propeller shaft, a propeller on said shaft externally of the housing,V a generally verticaly propeller adjusting rod extending down along the post and entering the other chamber, and connecting means disposed in said other chamber and connecting the lower end of Said rod and said propeller for adjusting the propeller by lneans of said rod.

In witness whereof, I hereunto subscribe my name this 11th day of April, l1931.

THEODORE L. SMITH. 

